"O Lord, bend over the battlements of glory and hear the cry of old Pittsburgh. O Lord, do you hear us? Lord, save tens of thousands of souls in this old city. Lord, everybody is helping. Lord, they are keeping their churches closed so tight that a burglar couldn't get in with a jimmy. Lord, the angels will shout to glory and the old devil will say, 'What did they shut up the churches of Pittsburgh for, when they have so many good preachers, and build a Tabernacle and bring a man on here to take the people away from me? O Lord, we'll win this whisky-soaked, vice-ridden old city of Pittsburgh and lay it at your feet and purify it until it is like paraffine." Sunday's sermon on prayer is entitled, "TEACH US TO PRAY" We live and develop physically by exercise. We are saved by faith, but we must work out our salvation by doing the things God wills. The more we do for God, the more God will do through us. Faith will increase by experience. If you are a stranger to prayer you are a stranger to the greatest source of power known to human beings. If we cared for our physical life in the same lackadaisical way that we care for our spiritual, we would be as weak physically as we are spiritually. You go week in and week out without prayer. I want to be a giant for God. You don't even sing; you let the choir do it. You go to prayer-meeting and offer no testimony. You are a stranger to the great privilege that is offered to human beings. Some of the greatest blessings that people enjoy come from prayer. In earnest prayer you think as the Lord directs, and lose yourself in him. Some people say: "It's no use to pray. The Lord knows everything, anyway." That's true. He does. He is not limited, as I am limited. He knows everything and has known it since before the world was. We don't know everybody who is going to be converted at this revival, but that doesn't relieve us of our duty. We don't know, and we must do the work he has commanded us to do.